Get sentence suggestions for specified texts in an array of TextInfo.
The default implementation splits the input text to words and returns
SentenceSuggestionsInfo which contains suggestions for each word.
This function will run on the incoming IPC thread.
So, this is not called on the main thread,
but will be called in series on another thread.
When you override this method, make sure that suggestionsLimit is applied to suggestions
that share the same start position and length.